Piston



May 22, 1951 J. DEMATTEIS 2,553,638

PISTON Filed Sept. 6, 1945 2 Sheets-.-Sheet 1 y 22, 1951 J. DEMATTEIS 2,553,638

PISTON Filed Sept. 6, 1945 2 SheetSSheet 2 a- .6 2f 52 5/ 3 5 3 m f Ufa) U01 lA/l DEN/77756 Patented May 22, 1951 UNITED STATES ATENT OFFKCE PISTON Julian Dematteis, Batavia, Iowa Application September 6, 1945, Serial No. 614,623

2 Claims. 1

This present invention relates to improvements in electrically welded steel pistons, but more particularly to pistons for internal combustion engines and the like. The main object of my invention is the construction of a high speed piston adapted for use in aeroplanes or motor cars that is of simple construction and can be manufactured at low cost.

It is a further object of the invention to design a piston the outer parts of which can be replaced Without removing the inner part or frame which is pivoted to the connecting rod, from the engine cylinder.

It is a further object of the invention to design a piston of the type characterized in the preceding paragraph which may be assembled by sliding the shell over the frame and then rotating the former on the latter to lock them both against axial separation.

With these and other objects in view the invention resides in the novelty of construction, combination and arrangement of parts specifically described in the following description and illustrated in the accompanying drawings and claimed in the appended claims.

In the drawings:

Figure l is a side elevation of the preferred embodiment of my invention partly broken away at the top and one side;

Figure 2 is a transverse section on line 2-2 of Figure 1 looking downward with the structure rotated approximately 90;

Figure 3 is a top plan view of the main frame and part of the cap;

Figure 4 is a perspective View of the outer shell;

Figure 5 is an edge view of the cap or cover for the piston;

Figure 6 is a partially broken away side view of the upper end of the shell, the outer cover and the asbestos chamber;

Figure '7 is a side View of the screw bolt and washer and a longitudinal section through the latch whereby the cover is secured to the main frame and bottom of asbestos chamber;

Figure 8 is a top plan View of the latch;

Figure 9 is a top plan view of the washer.

In the drawings in which like characters of reference designate like or similar parts throughout the several views, numeral 2 (Figure 1) denotes a connecting rod of the piston to be described and slidable in a cylinder of an internal combustion engine. The connecting rod has a split opening for a bushing 3 in which the wrist pin 6 is journaled and split arms 5 which may be tightened by a take-up bolt 6 having nuts l.

The wrist pin of the standard one inch hollow type is mounted in the inner part or main frame 8 of the piston. The main frame has a central rectangular opening 9 for the connecting rod and is provided on the top surface with opposed cut-outs 10 whereby the corner edges near the ends of the take-up bolt are removed to provide access for the wrenches used in tightening the nuts on this bolt or replacing the latter or the bushing or wrist pin. The location of the take-up bolt is determined by the fact that the piston shell still to be described has to be removed befor replacement referred to can be made. The frame is a one-piece steel casting of substantially rectangular transverse section. The deviation from the true rectangular transverse section lies in the fact that the outer corners of struts a which extend substantially above and below the remaining portion (Figure 1, 2) are rounded off and replaced by fragmentary exterior cylindrical surfaces indicated by the dotted lines l l in Figure 2. Each strut is connected by a brace b extending parallel to the wrist pin to the strut near the opposite end of that pin.

From each of these surfaces extend radially three axially spaced lugs l2, also rounded and parallel to the surfaces H and. of dovetailed transverse section.

The outer part of the piston is a cylindrical shell 13 which is telescoped over the main frame described and consists of a pair of semi-cylindrical halves M. at their straight longitudinal edges to form a cylinder. The construction of the latter in halves is required by the fact thatmachining or milling operations are to be performed upon its interior or concave surface. A pair of parallel grooves Eli are milled upon the concave side of each shell half and extend parallel to the axis of the shell. The transverse cross section of these grooves is dovetailed and fits the cross section of the lugs I2 which because of the superposed and aligned relation of threelugs at each corner do not offer any obstruction to telescoping the assembled shell over the main frame in a manner still to be described in detail. From the right-hand side of each groove extend in a clockwise sense three axially spaced peripheral grooves [6 which have an axial and radial width slightly larger than the corresponding width of the lugs H2. The axial spacing'of the peripheral grooves is the same as the corresponding spacing of the lugs. After the shell has been lowered over and about the main frame, it may be locked by a small counterclockwise displacement relative to the main frame These. halves are welded together.

which displacement locates the lugs in the peripheral extension grooves.

The exterior of the shell is provided with a pair of peripheral grooves ll, each formed below one of the two upper inner peripheral grooves and receiving a split piston ring H3. The latter has an intermediate peripheral groove 19 the bottom of which is in communication with the outer ends of a plurality of radial holes 29. The inner ends of these holes are in communication with the nearest groove i5 which conducts the oil splashed from the crankcase to the holes.

The top end of the main frame is formed into an asbestos chamber b a circular bottom 2i extending between the corner struts a, a cylindrical wall 22 arising from the bottom and integral with the struts. The cylindrical wall 22 has several slits a which allow for expansion due to heat. On one side of each slit a thin piece h of spring steel is brazed to the inner surface of the wall and covers the slit, thereby preventing the oil from coming in contact with the asbestos in the chamber while not interfering with heat expansion.

The chamber is filled with asbestos packing 23 with a View of protecting the oil in the crankcase from the heat of the gases exploding above the piston and in the engine cylinder. such insulation the heat would turn the oil in the crankcase black and disable it from functioning as a lubricant. The inner portions 24 of the corner struts extend into the chamber beyond the interior surface of the cylindrical wall (Figure 3) and are each received into a notch 25 formed upon the underside of a cover 26 (Figures 5 and 6).

The latter is substantially circular and resembles an inverted cup (Figure 6) and has a radially extending flange 21 near its lower end. A gasket ring 28 rests on the flange 21 and from the lower surface of the latter extends a short cylindrical flange 29 which fits into the cylindrical wall of the asbestos chamber (Figure 6). The flat top portion 39 of the cover has four spaced countersunk bolt apertures 31 each for a rivet bolt 32 which passes through the asbestos packing and a hole in the bottom 2| of the asbestos chamber and has a head on its lower end bearing against the underside of such bottom.

The portion of each rivet between the lower side of the cover and upper side of the bottom of the asbestos chamber is surrounded by a spacing sleeve 33.

In the circumferential marginal portion of the cover top is formed a depression 34 which has a rounded end and opens at the circumference of the top and receives a correspondingly formed latch 35. The inner end of the latter is rounded to conform to the corresponding end of the socket (Figure 8) and the opposite end 35 is outwardly beveled and the intermediate portion has a countersunk aperture 31 with a radial notch 38. A correspondingly shaped frusto-conical washer 39 with a radial tongue 40 fits into the aperture and notch and receives the stem of a screw bolt 4| with a notched head. The latter is received into the countersunk aperture in the washer and the stem passes through the asbestos packing and bottom 2| and is threaded at its lower end into a nut 42 welded to the lower side of the bottom of the asbestos chamber (Figure 6). The outer beveled end 36 of the latch 35 in assembled con- Without 4 dition extends above the gasket ring 28 and beneath the outwardly and upward bevel formed on the lower surface of an inwardly extending flange 43 formed on the upper open end of the shell (Figure 6).

In order to assemble the piston in the preferred manner i. e. within the engine cylinder within which it is to operate, the head of the engine or motor is removed. The main frame including the cover but without thelatch 35 is connected to the crank shaft by the connecting rod. The two halves of the outer shell have been welded together at the narrow longitudinal edges. The four grooves on the inner side of such shell are brought into alignment with the lugs on the main frame. The shell is then lowered into the engine cylinder and receives therein the main frame, after which the head of the engine may be replaced.

While I have described in detail the construction of the preferred embodiment of my invention and illustrated such construction in the accompanying drawings, I desire it to be understood that these structural details are not to be considered as limitations, but as mere examples of my invention the spirit or scope of which is to be judged by the appended claims.

What I claim and desire to secure by Letters Patent is:

1. A piston comprising an inner frame, an outer shell surrounding the frame and locked thereon against axial motion and releasable therefrom by rotation, an asbestos chamber in the upper end portion of the shell, a lid for closing the upper end of the chamber and shell and rivets with spacing sleeves for connecting the lid to the bottom of the chamber.

2. A piston comprising an inner frame, an outer shell surrounding the frame and locked thereon against axial motion and releasable therefrom by rotation, an asbestos chamber in the upper end portion of the shell, a lid for closing the upper end of the chamber and shell and riveted to the bottom of the chamber, and latch means cooperating with the lid and shell and bolted to the bottom of the chamber.

JULIAN DEMATTEIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 331,831 Simpson et al Dec. 8, 1885 1,329,823 Parkhurst Feb. 3, 1920 1,331,555 Barbarou Feb. 24, 1920 1,332,213 Haas Mar. 2, 1920 1,388,552 Corser Aug. 23, 1921 1,460,041 Smith June 26, 1923 1,557,871 Painter Oct. 20, 1925 1,601,776 Sheirling et a1. Oct. 5, 1926 1,605,838 Hawley Nov. 2, 1926 1,789,570 Teetor Jan. 20, 1931 1,884,050 McCormick Oct. 25, 1932 1,917,706 Even July 11, 1933 2,361,095 l-Iarrah Oct. 24, 1944 FOREIGN PATENTS Number Country Date 18,640 Great Britain Oct. 29, 1891 

